San Onofre nuclear plant can withstand up to 7.0 quake, is protected by a 25-foot tsunami wall, Edis

[nadinbrzezinski]

Operators of the concrete-domed San Onofre nuclear plant Monday were trying to reassure jittery Southern California residents that the nuclear disaster unfolding in Japan won't happen here.

The 84-acre generating station in the northern corner of San Diego County is built to withstand a magnitude 7.0 earthquake, said Gil Alexander, a spokesman for the generation station's operator, Southern California Edison. That is greater than the 6.5 shaker that scientists predicted could strike the plant before it was built 42 years ago, he said. But it's less than the 8.9 quake that hit Japan last week.

A 25-foot-high "tsunami wall" of reinforced concete was also erected between the plant and the adjacent ocean, a height based on scientists' best estimates of the potential threat, he said. The geological fault most likely to directly threaten San Onofre lies about 5 miles offshore, Alexander said.

The Nuclear Regulatory Commission also sought to allay fears that small releases of radiation from Japan's crippled Fukishima reactors were a threat to the U.S.

Available information indicates that weather conditions have carried any radioactive vapors out to sea and away from the Japanese population. Given the thousands of miles between the two countries, Hawaii, Alaska, the U.S. territories and the U.S. West Coast are not expected to experience any harmful levels of radioactivity, the commission said Monday.

http://latimesblogs.latimes.com/lanow/2011/03/san-onofre-nuclear-plant-can-withstand-quakestsunamis-officials-say.html

Now you will see them trying to tell us that nothing is going or could possibly go wrong... they are starting to campaign to get the people asleep.

Idiots, SO Cal has the potential of an 8 in the richter scale...

And yes we know they did this to very LOCAL geology, I wonder if they also looked up the words liquefaction. No it is not calming me down... at all.

[Nederland]

1. How much radiation was released from the Fukushima complex?

Does anyone know the actual readings?

[nadinbrzezinski]

6. at the plant site they released

1000 msiverts... that is 10 rads

1 msievert= 0.02 rads...

At the outside of the plant they got 400 Msieverts.

That is the max release we have seen.

No, this is not a joke, but it is not YET even close to deadly. What it is... well... any exposure is not healthy...

They have released these technical things with the International Atomic Energy commission

So far they admit a L-4 disaster, IMO is getting close to a 6

[Nederland]

13. True

Not even close to deadly, at least at this point in time.

To put it in perspective, a person in an airplane traveling at 35,000 feet receives 6 Msieverts per hour. By my math this means the average pilot or flight crew member is often exposed to more radiation every month than someone who was standing right outside the plant when the radiation was released. True?

[nadinbrzezinski]

14. Except that we have people in isolation right now

due to exposure...

And to put it in real perspective, this cumulative effect will cause cancer clusters.

[FBaggins]

17. In isolation?

Is radiation poisoning contageous now?

And to put it in real perspective, this cumulative effect will cause cancer clusters.

Probably so.

[reorg]

20. dead wrong

Somebody else has distributed this myth here before, but a pilot does not receive 6 "mSv" (millisievert) per hour, he receives 6 "μSv" (microsievers) per hour.

So, to put it in perspective, the reported 3 Sievers per hour are how much more? 500,000 times?



On edit: Perhaps the poster is correct and the press reports are confusing things (see quote from Der Spiegel). Usually, mSv means millisievert, one thousands of one Sievert:

http://www.world-nuclear.org/education/ral.htm (also in many other sources).

I understood the reported maximum level on Sunday as 1.5 Sievert (1,500 mSv), thus the doubling today as 3.1 Sievert (3,120 mS), but in the latest report at Kyodonews they say "microsievert".

[FBaggins]

22. Can you link to reporting of that 3 Sv/hr?

Ignoring the fact that since it's a measure of equivelent dose, it isn't something they could just wave a geiger counter at... I'd still like to see the source.

That's a level that would kill you pretty quickly.

[reorg]

24. I already cited it several times

but you are correct, it also says "microSievers" - either I am confused or they have reported different measures

"Prior to the second full exposure of the rods around 11 p.m. Monday, radiation was detected at 9:37 p.m. at a level twice the maximum seen so far -- 3,130 micro sievert per hour -- near the main gate of the No. 1 plant, according to TEPCO."

http://english.kyodonews.jp/news/2011/03/77959.html

see eg Der Spiegel (on the level reported on Sunday):

"Experts at the site reported that radiation levels of one sievert per hour had been measured near the reactor. This is a high level, but nothing compared with the 200 sievert per hour to which some emergency workers in Chernobyl were exposed."

http://www.spiegel.de/international/world/0,1518,750773,00.html


So, if the current level is measured in micro, not millisievers, it would appear that it is not 500,000 times the level a pilot receives during a long distance flight, but just 500 times.



"A single, long international flight will expose you to a week's worth of natural background radiation. That's far from a health concern, even for pregnant women. But aviation workers can easily exceed the groups' recommended limits. For example, a pregnant flight attendant working a London-to-Chicago route for just 100 hours (about 12 trips) would exceed the safe exposure for her fetus. For air crews, the limit is 20 millisieverts (mSV) a year. (For scale, a person at ground level gets about 2.4 mSv of natural background radiation a year.)"

http://www.airspacemag.com/need-to-know/NEED-radiation.html

[Nederland]

27. 3,130 micro sieverts per hour, for how long?

The article doesn't say, and it matters.

[reorg]

31. what do you mean: how long did they measure or how long were workers exposed?

I don't know anything outside of what the article says.

[Nederland]

38. For what length of time was the reading at that level?

They reported a reading of 3,130 micro sieverts per hour. So my question is, was the 3,130 reading just a spike that lasted for a couple seconds when some gas was released, or was it a continous reading that lasted for hours?

Also, this report indicates that the 3,130 reading was inside the plant, not outside: http://www.news.com.au/world/magnitude-quake-strikes-japan/story-e6frfkyi-1226019903430

[reorg]

44. Kyodo News says "at the plant's premises"

so, whatever that means, the readings appear to oscillate between a few hundred and 3,130 micro sievert (per hour):

"On Monday, radiation at the plant's premises rose over the benchmark limit of 500 micro sievert per hour at two locations, measuring 751 micro sievert at the first location at 2:20 a.m. and 650 at the second at 2:40 a.m., according to the report.

The hourly amounts are more than half the 1,000 micro sievert level to which people are usually exposed in one year.

The maximum level detected so far around the plant is 1,557.5 micro sievert logged Sunday."

http://english.kyodonews.jp/news/2011/03/77729.html

"Prior to the second full exposure of the rods around 11 p.m., radiation was detected at 9:37 p.m. at a level twice the maximum seen so far -- 3,130 micro sievert per hour, according to TEPCO."

http://english.kyodonews.jp/news/2011/03/77943.html


I suppose dozens of emergency workers have by now received more than the allowed dose for one year (20 millisievert).


"20 mSv/yr averaged over 5 years is the limit for radiological personnel such as employees in the nuclear industry, uranium or mineral sands miners and hospital workers (who are all closely monitored)."

http://www.world-nuclear.org/education/ral.htm

[nadinbrzezinski]

52. Conversions

SI multiples and conversions

Frequently used SI multiples are the millisievert (1 mSv = 10−3 Sv) and microsievert (1 μSv = 10−6 Sv) or (1 mSv = 0.001 Sv) and (1 μSv = 0.000001 Sv).
An older unit of the equivalent dose is the rem (Röntgen equivalent man). In some fields and countries, the rem and millirem (abbreviated mrem) continue to be used along with Sv and mSv, causing confusion. Here are the conversion equivalences:
1 Sv = 100 rem
1 mSv = 100 mrem = 0.1 rem
1 μSv = 0.1 mrem
1 rem = 0.01 Sv = 10 mSv
1 mrem = 0.00001 Sv = 0.01 mSv = 10 μSv

http://en.wikipedia.org/wiki/Sievert

[FBaggins]

34. The level fell off quite rapidly.

I think this refers to one of the measurements made right after an intentional release of pressure a couple days ago. It isn't like a lump of radioactive material that just keeps up the activity level. It was mostly gaseous and would dissipate pretty rapidly (and go other places).

[Nederland]

40. That is what I would think too

However, I haven't seen anything to verify. The geek in me wishes that TEPCO would setup a Twitter feed that posted the current reading every minute. Release the raw data in an automated fashion, and let the spin doctors on both sides pontificate as they desire. That type of transparency is what the Japanese people deserve.

[nadinbrzezinski]

42. They are releasing technical data to the IAEC

go there

Oh and SO FAR we have had releases that are not close to deadly.

Inside the plant they are dangerous, but not deadly.

Remember, not you, everybody else, they are cummulative

[Nederland]

48. "They are cummulative"

Yes they are, and that could soon be a problem. I can imagine a time in the near future when the people that understand the plant best and know what to do in this emergency are forced to leave because they have hit their limit of safe exposure.

[nadinbrzezinski]

50. We are getting close to that point

How many 1000 times safe limit (I went wtf do you people mean) can they take?

[Nederland]

26. The units in the post I was responding to were wrong

The poster (post #6) specified that at the plant site they released 1000 msieverts, and outside the plant they released 400 Msieverts. Standard SI unit abbreviations denote that the prefix "m" means milli (one thousandth) and the prefix "M" means mega (million). Now I assume we can agree that the release outside the plant was not actually 400 million sieverts, because everyone would be dead. My mistake was in thinking the poster meant "micro" when they typed the capital "M", which is why I responded the way I did. I'm trying to find out what the actual reading outside the plant was so I can come up with an accurate comparative example.

BTW, the correct unit of radiation exposure is seivert, not sievers.

[FBaggins]

32. "not actually 400 million sieverts, because everyone would be dead."

Yeah... and that could be more radiation than the entire core holds (especially when you back out of Sv to activity measures).

Still it's not an uncommon error. Half a dozen different units measuring different thing - added to the ability to measure many decimal places down.

[nadinbrzezinski]

41. They are... why it is best to just go to the IAEC

[CreekDog]

37. There's 20 million people down in that area, unlike the area in Japan

I think that's a significant difference.

and nevermind that the prevailing winds very reliably bring everything from the coast inland.

[Nederland]

39. Prevailing winds are to sea, not inland (nt)

[CreekDog]

43. in southern California? No.

(taking back my emotion since you misunderstood me)

[Nederland]

46. Sorry

I thought you were talking about Japan.

[robdogbucky]

49. Tokyo Metropolitan Area, just about 130 miles from Fukushima

has 39 million people, the largest such metropolitan area in the world.

"Tokyo (東京, Tōkyō?, "Eastern Capital"), officially Tokyo Metropolis (東京都, Tōkyō-to?),<2> is one of the 47 prefectures of Japan. It is located on the eastern side of the main island Honshū and includes the Izu Islands and Ogasawara Islands. Tokyo Metropolis was formed in 1943 from the merger of the former Tokyo Prefecture (東京府, Tōkyō-fu?) and the city of Tokyo (東京市, Tōkyō-shi?). Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family.

The Tokyo Metropolitan government administers the twenty-three special wards of Tokyo, each governed as a city, that cover the area that was the city of Tokyo as well as 39 municipalities in the western part of the prefecture and the two outlying island chains. The population of the special wards is over 8 million people, with the total population of the prefecture exceeding 13 million. The prefecture is part of the world's most populous metropolitan area with 35 to 39 million people (depending on definition) and the world's largest metropolitan economy with a GDP of US$1.479 trillion at purchasing power parity in 2008, ahead of New York City, which ranks second on the list.."

http://en.wikipedia.org/wiki/Tokyo



The prevailing winds on the entire west coast of this North American Continent flow from west to east, unless there is a gradient wind, brought on by stagnant high pressure systems, which reverses that to create the famous Santa Ana Winds. But that is the only time the wind blows from the east down there.



CLIMATE OF CALIFORNIA

"...WINDS – California lies within the zone of prevailing westerlies and on the east side of the semi-permanent high pressure area of the northeast Pacific Ocean. The basic flow in the free air above the State, therefore, is from the west or northwest during most of the year. The several mountain chains within the State, however, are responsible for deflecting these winds and, except for the immediate coast, wind direction is likely to be more a product of local terrain than it is of prevailing circulation..."

http://www.wrcc.dri.edu/narratives/CALIFORNIA.htm




Sheeesh, this stuff is easy.

[bergie321]

15. "not YET even close to deadly"

Except for the guy that died...

[Nederland]

16. Did he die from radiation exposure or the explosion? (nt)

[fittosurvive]

53. "Except for the guy that died..."

It makes you wonder if he ever considered the perils of inhabiting an island situated on four tectonic plates.

[reorg]

18. not the max

A few hours ago, Kyodonews reported:

"Prior to the second full exposure of the rods around 11 p.m., radiation was detected at 9:37 p.m. at a level twice the maximum seen so far -- 3,130 micro sievert per hour, according to TEPCO."

http://english.kyodonews.jp/news/2011/03/77943.html

1,000 mSv (1 sievert) in a short-term dose is about the threshold for causing immediate radiation sickness in a person of average physical attributes, but would be unlikely to cause death. Above 1000 mSv, severity of illness increases with dose. If doses greater than 1000 mSv occur over a long period they are less likely to have early health effects, but they create a definite risk that cancer will develop many years later.

Above about 100 mSv, the probability of cancer (rather than the severity of illness) increases with dose. The estimated risk of fatal cancer is 5 of every 100 persons exposed to a dose of 1000 mSv (ie. if the normal incidence of fatal cancer were 25%, this dose would increase it to 30%).

50 mSv is, conservatively, the lowest dose at which there is any evidence of cancer being caused in adults. It is also the highest dose which is allowed by regulation in any one year of occupational exposure. Dose rates greater than 50 mSv/yr arise from natural background levels in several parts of the world but do not cause any discernible harm to local populations.

20 mSv/yr averaged over 5 years is the limit for radiological personnel such as employees in the nuclear industry, uranium or mineral sands miners and hospital workers (who are all closely monitored).

10 mSv/yr is the maximum actual dose rate received by any Australian uranium miner.

3-5 mSv/yr is the typical dose rate (above background) received by uranium miners in Australia and Canada.

3 mSv/yr (approx) is the typical background radiation from natural sources in North America, including an average of almost 2 mSv/yr from radon in air.

http://www.world-nuclear.org/education/ral.htm

[FBaggins]

36. You've got micro sievert in your title, but millisievert in your description.

They're off by a factor of 1,000.

3,130 micro sieverts (assuming it continued for an hour... which it didn't), is 3/1,000ths of a Sv.

So you're really not talking about that large a dose.

[Statistical]

2. Tsuanmi wall in Japan might have saved the generators.

Everything indicates the reactor, containment building, and core systems survived both the earthquake and tsunami.

The plant SCRAMED (emergency automatic shutdown) and generators kicked on to power main cooling pumps. The generators remained online for about 1 hour before failing. Was that because they were destroyed by the Tsunami?

Would 25foot tsunami walls have helped?

[buddysmellgood]

28. I'm wondering the same thing. Was it flooding that put electrical equipment under water and

prevented new generators from being hooked up. Would similar flooding happen here?

[Statistical]

30. At this point we don't know but after TMI I am sure there will be significant analysis.

We made significant changes to reactors, safety systems, training, and designs after TMI.

I am sure there will be "lessons learned" to use engineer speak after this disaster.

Some things have gone wrong.
Generators went offline. Why?
New generators couldn't be connect. Why?
Hydrogen explosions despite system designed to flare hydrogen. Why?

Some thing went right (so far).
RPV have held.
RPV survived two explosions.
There has been minimal loss of life.

So some analysis needs to be done to identify points of failure and improve existing systems.

[buddysmellgood]

54. Although now it seem there may be a leak at #2

[robdogbucky]

51. I have seen reports that other tsunami walls along that north coast

failed to stop the onslaught of the tidal wave that hit.

You know that village that the residents were able to flee to higher ground and then videotaped it as it came in, had a wall.

No help for this whatsoever.

This quake and subsequent tsunami exceeded the wildest guesses of planners over there.

[aquart]

3. A 7.0? Is it a tinker toy?

7.0's are for children. We're into adult earthquakes now.

[ChairmanAgnostic]

5. Even Chicago skyscrapers have a higher tolerance

because of the New Madrid fault.

I think they designed them to 8.0 or 8.2 in mind.

[JuniperLea]

4. I've watched liquifaction with my own eyes...

This does absolutely nothing to calm my nerves.

[nadinbrzezinski]

7. I know, I know

it is good they got a tsunami wall... but hey...

the tappy feet brigade will be here soon

[petronius]

47. The structure under SO is apparently the San Mateo Formation, a sandstone

It's not prone to liquefaction; shaking would be the hazard there...

[Duer 157099]

8. Hah! I laugh at your 25-foot concrete wall!

I saw houses AND walls whooshing by in the Japanese tsunami!

Wall my ass.

[hobbit709]

9. There have been tsunamis much higher than 25 ft.

And there certainly have been quakes much higher than a 7.

That's like saying your car can survive a 30 mph crash while driving on the Interstate at 70.

[itsrobert]

11. Yes, once the wall is topped, the water would be trapped around the plant

with no place to go. They would probably have the marines blow a hole into the wall.

[itsrobert]

10. So what happens when the water goes around the wall and comes back into the compound?

"A 25-foot-high "tsunami wall" of reinforced concete was also erected between the plant and the adjacent ocean,"


I saw a water flowing to any available low spot in the Japan Tsunami. Looks like after getting around the wall the water would flow back into where the plant is at. And worse, the water wouldn't be able to escape because of a big ass 25 foot wall blocking its path back into the ocean.

[regnaD kciN]

12. So, in other words...

...it's built to withstand a quake a little more than 1/100th the strength of the Japanese quake.

Furthermore, the Diablo Canyon nuke plant up the coast, close to the San Andreas fault, is built to withstand a 7.5 quake. A bit better, true, but has anyone determined that quakes larger than 7.5 simply don't happen on the west coast? :crazy:

At least WPPSS, Dixie Lee Ray's scheme to turn Washington into a nuke-powered state, fell apart before it could even get started -- and the Oregon plant nearest to the coast was shut down and demolished several years ago.

[wiggs]

19. I believe San Onofre is past its decommission date. nt

[brooklynite]

21. So, not much good then, hmm?

Japoan quake was about 100 times stronger (if I understand the Richter Scale) and the wave would have been five feet higher

[FBaggins]

23. Not much good if they got a 9 with a tsunami that size.

They really aren't prone to such.

The most damaging tsunami in West Coast (not counting AK/HI) history killed something like a dozen people. The type of fault line and placement of Japan relative to it make them far more likely there than in CA.

[Vinca]

25. Isn't it like night and day - the difference between 7.0 and 8.9?

And I've heard the tsunami described as 4 stories high.

[Control-Z]

33. I believe

8.9 shaking is something like 100 times 7.0 but the energy released is like 1000 times greater.

[Better Believe It]

35. A 7.1 is twice a strong as a 7.0. All bets are off!

[Better Believe It]

29. How will it do in a 7.1 quake? Just askin.

[nadinbrzezinski]

45. Just sent an email to the WH

asking them to stop lying about this. No, all is not ok... and they should be doing a bottom up review on it...

[WillyT]

55. Is That The One Where They Installed The Shit Upside-Down And Backwards ???

Or was that Diablo Canyon?

:evilgrin:

:hi: